A197540 Number of nX3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,2,1,1,1 for x=0,1,2,3,4

2, 8, 11, 24, 61, 121, 270, 614, 1296, 2973, 6574, 14527, 32621, 72032, 160402, 357304, 792903, 1765982, 3926185, 8727963, 19420018, 43174998, 96024756, 213571465, 474912978, 1056243677, 2348975193, 5223841988, 11617743070, 25836617638

Offset

1,1

Comments

Every 0 is next to 0 2's, every 1 is next to 1 2's, every 2 is next to 2 1's, every 3 is next to 3 1's, every 4 is next to 4 1's

Column 3 of A197545

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 2*a(n-1) +a(n-3) -2*a(n-4) +7*a(n-5) -a(n-6) -6*a(n-7) +a(n-8) -16*a(n-9) +16*a(n-10) -7*a(n-11) -27*a(n-12) +45*a(n-13) -25*a(n-15) +19*a(n-16) +8*a(n-17) -24*a(n-18) +16*a(n-19) -8*a(n-20) +2*a(n-21)

Example

Some solutions for n=4
..2..1..0....1..0..0....1..1..2....0..0..0....0..0..0....0..0..1....2..1..0
..1..0..0....2..1..0....2..1..1....0..0..0....0..0..0....0..1..2....1..0..0
..0..0..1....2..1..1....2..1..0....0..0..1....1..0..0....0..1..2....1..0..0
..0..1..2....1..1..2....1..0..0....0..1..2....2..1..0....0..0..1....2..1..0

Crossrefs

Sequence in context: A234924 A336771 A174114 * A089118 A146480 A093918

Adjacent sequences: A197537 A197538 A197539 * A197541 A197542 A197543

Keyword

nonn

Author

R. H. Hardin Oct 16 2011

Status

approved